Answer:
ΔT = Tfinal − Tinitial = 150°C − 35.0°C = 125°C
given the specific heat of iron as 0.108 cal/g·°C
heat=(100.0 g)(0.108 cal /g· °C )(125°C) =
100x 0.108x125= 1350 cal
Iron bending is just a physical change because the iron has only changed shape but there is no new substance. Iron rusting is a chemical change because there is a new substance which is rust.
The standard formation equation for glucose C6H12O6(s) that corresponds to the standard enthalpy of formation or enthalpy change ΔH°f = -1273.3 kJ/mol is
C(s) + H2(g) + O2(g) → C6H12O6(s)
and the balanced chemical equation is
6C(s) + 6H2(g) + 3O2(g) → C6H12O6(s)
Using the equation for the standard enthalpy change of formation
ΔHoreaction = ∑ΔHof(products)−∑ΔHof(Reactants)
ΔHoreaction = ΔHfo[C6H12O6(s)] - {ΔHfo[C(s, graphite) + ΔHfo[H2(g)] + ΔHfo[O2(g)]}
C(s), H2(g), and O2(g) each have a standard enthalpy of formation equal to 0 since they are in their most stable forms:
ΔHoreaction = [1*-1273.3] - [(6*0) + (6*0) + (3*0)]
= -1273.3 - (0 + 0 + 0)
= -1273.3
O2 is an example of a molecule
Answer:
A. Na₂SO₄ and HCl
C. Polar solutes are soluble in polar solvents but are insoluble in non-polar solvents Non-polar solutes are insoluble in polar solvents but are are soluble in non-polar solvents
Ionic solutes are soluble in polar solvents but are insoluble in non-polar solvents.
Like dissolves like simply means that molecules of substances having similar chemical properties dissolve in each other
Explanation:
A. Ionic substances like Na₂SO₄ are composed of charged particles called ions. These ions are either positively charged or negatively charged, therefore, they are attracted to substances of opposite charges. Also, polar molecules like HCl contains two oppositely charged ends. A polar solvent consists of molecules with two oppositely charged ends, therefore, ionic substances as well polar substances dissolve in them according to the concept of like dissolves like.
Gasoline being non-polar will only dissolve in like substances, polar solvents.
C. Polar solutes are soluble in polar solvents but are insoluble in non-polar solvents Non-polar solutes are insoluble in polar solvents but are are soluble in non-polar solvents
Ionic solutes are soluble in polar solvents but are insoluble in non-polar solvents.
The statement "Like dissolves like" simply means that molecules of substances having similar chemical properties dissolve in each other. For example gasoline, a non-polar substance will dissolve only in a non-polar solvent like kerosene. Also, HCl, a polar molecule will dissolve in a polar solvent like water.
